Human IMPDH2 treated with ATP, IMP, and 20 mM GTP. Fully compressed filament segment reconstruction.

Experimental Data Snapshot

  • Resolution: 3.21 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: SINGLE PARTICLE 

wwPDB Validation   3D Report Full Report

This is version 1.1 of the entry. See complete history


Cryo-EM structures demonstrate human IMPDH2 filament assembly tunes allosteric regulation.

Johnson, M.C.Kollman, J.M.

(2020) Elife 9

  • DOI: https://doi.org/10.7554/eLife.53243
  • Primary Citation of Related Structures:  
    6U8E, 6U8N, 6U8R, 6U8S, 6U9O, 6UA2, 6UA4, 6UA5, 6UAJ, 6UC2, 6UDO, 6UDP, 6UDQ

  • PubMed Abstract: 

    Inosine monophosphate dehydrogenase (IMPDH) mediates the first committed step in guanine nucleotide biosynthesis and plays important roles in cellular proliferation and the immune response. IMPDH reversibly polymerizes in cells and tissues in response to changes in metabolic demand. Self-assembly of metabolic enzymes is increasingly recognized as a general mechanism for regulating activity, typically by stabilizing specific conformations of an enzyme, but the regulatory role of IMPDH filaments has remained unclear. Here, we report a series of human IMPDH2 cryo-EM structures in both active and inactive conformations. The structures define the mechanism of filament assembly, and reveal how filament-dependent allosteric regulation of IMPDH2 makes the enzyme less sensitive to feedback inhibition, explaining why assembly occurs under physiological conditions that require expansion of guanine nucleotide pools. Tuning sensitivity to an allosteric inhibitor distinguishes IMPDH from other metabolic filaments, and highlights the diversity of regulatory outcomes that can emerge from self-assembly.

  • Organizational Affiliation

    Department of Biochemistry, University of Washington, Seattle, United States.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Inosine-5'-monophosphate dehydrogenase 2
A, B, C, D, E
A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P
519Homo sapiensMutation(s): 0 
Gene Names: IMPDH2IMPD2
UniProt & NIH Common Fund Data Resources
Find proteins for P12268 (Homo sapiens)
Explore P12268 
Go to UniProtKB:  P12268
PHAROS:  P12268
GTEx:  ENSG00000178035 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP12268
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
GTP (Subject of Investigation/LOI)
Query on GTP

Download Ideal Coordinates CCD File 
AA [auth C]
DA [auth D]
EA [auth D]
HA [auth E]
IA [auth E]
AA [auth C],
DA [auth D],
EA [auth D],
HA [auth E],
IA [auth E],
LA [auth F],
MA [auth F],
PA [auth G],
QA [auth G],
R [auth A],
S [auth A],
TA [auth H],
UA [auth H],
V [auth B],
W [auth B],
Z [auth C]
C10 H16 N5 O14 P3
ATP (Subject of Investigation/LOI)
Query on ATP

Download Ideal Coordinates CCD File 
BA [auth C]
FA [auth D]
JA [auth E]
NA [auth F]
RA [auth G]
BA [auth C],
FA [auth D],
JA [auth E],
NA [auth F],
RA [auth G],
T [auth A],
VA [auth H],
X [auth B]
C10 H16 N5 O13 P3
IMP (Subject of Investigation/LOI)
Query on IMP

Download Ideal Coordinates CCD File 
CA [auth D]
GA [auth E]
KA [auth F]
OA [auth G]
Q [auth A]
CA [auth D],
GA [auth E],
KA [auth F],
OA [auth G],
Q [auth A],
SA [auth H],
U [auth B],
Y [auth C]
C10 H13 N4 O8 P
Experimental Data & Validation

Experimental Data

  • Resolution: 3.21 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: SINGLE PARTICLE 

Structure Validation

View Full Validation Report

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United States5R01GM118396-04

Revision History  (Full details and data files)

  • Version 1.0: 2020-03-25
    Type: Initial release
  • Version 1.1: 2024-03-20
    Changes: Data collection, Database references